Never-ending Pain

I feel like I can't breathe. I always have a reaction when I see him post something. It's been years now and I still feel this way. I don't understand what's wrong with me. I've been in relationships before and even one since and no other time hurt for this long.

I've heard people talk about "the one that got away" and thought that seemed a little too Disney to me, but now I think I understand. The desire to be with that person doesn't subside over time the way it does with other relationships. The heartbreak doesn't stop and I can't figure out how to move on. The worst part is that he was more like "the one I pushed away" because I was the unhealthy one in the relationship. I still am.

I can already hear rational people giving me advice about how to fix myself, but if I truly am what I expect I am, there is very little hope that I will ever get better. That is not even my self-pity or depression talking. That is the viewpoint of professionals. So it seems that the relationship was doomed from the beginning and only in the past few months can I truly understand why. Despite the bleak outlook, I am still trying to get better. Although, for the first time in my life, I am finally trying to get better simply for myself and not someone I'm dating at the time.

The sad conclusion I've come to is that I cannot be in a relationship and I have had to accept that I may never be in a relationship again. My dreams of one day getting married are crushed, but I am finally able to accept that this is for the best. I cannot continue to hurt the people I date and I know that other peoples' lives will be better for never having been with me. This is one of the hardest realizations I've ever had to come to in my life.

Still...how do I stop loving him? How can I let him go and be with the new person he loves? I know he deserves that. I want him to be happy. I really do. I just keep finding myself wishing that he could have been happy with me; that I was the kind of person that had that ability; that I could have been for him what he was for me. When will I be able to let him go and stop this never-ending pain?